Ultrasound produces pictures of the inside of the body using sound waves. The technique is safe, non-invasive and painless.
Ultrasound imaging, also called sonography, involves the use of a small transducer and ultrasound gel placed directly on the skin. High-frequency sound waves are transmitted from the probe through the gel into the body. The transducer collects the sounds that bounce back and a computer then uses those sound waves to create an image. Ultrasound exams do not use ionizing radiation, thus there is no radiation exposure to the patient. Because ultrasound images are captured in real-time, they can show the structure and movement of the body's internal organs, as well as blood flowing through blood vessels.
The procedure may be used to diagnose a variety of conditions, assess organ damage, monitor pregnancy, evaluate pain, swelling and infection, guide procedures like needle biopsies, and much more. Ultrasound can be used for most of the body’s internal organs, including the heart, liver, gallbladder, kidneys, bladder, uterus and pancreas, among others.
Learn how to prepare for an ultrasound and what to expect before, during and after the procedure.
Before the Procedure
You should wear comfortable, loose-fitting clothing for your ultrasound exam. You may need to remove all clothing and jewelry and wear a gown during the procedure.
Preparation for the procedure will depend on the type of exam. For some scans your doctor may instruct you not to eat or drink for as many as 12 hours before your appointment. For others you may be asked to drink up to six glasses of water two hours prior to your exam and avoid urinating so that your bladder is full when the scan begins.
During the Procedure
For most ultrasound exams, you will be positioned lying face-up on an exam table that can be tilted or moved. Patients may be turned to either side or on occasion placed in a face-down position to improve the quality of the images.
The radiologist or sonographer will apply a warm water-based gel to the area of the body being studied. The gel will help the transducer make secure contact with the body and eliminate air pockets between the transducer and the skin that can block sound waves from passing into your body. The transducer is placed on the body and moved back and forth over the area of interest until the desired images are captured.
There is usually no discomfort as the transducer is pressed against the area being examined. However, if scanning is performed over an area of tenderness, you may feel pressure or minor pain from the transducer.
In some ultrasound studies, the transducer is attached to a probe and inserted into a natural opening in the body, like the esophagus, rectum or vagina.
Once the imaging is complete, the clear ultrasound gel will be wiped off your skin.
Most ultrasounds are completed within 30 minutes, although more extensive exams may take up to an hour.
After the Procedure
When the exam is complete, you will be asked to wait until the technologist verifies that the images are of high enough quality for accurate interpretation. Once this has been confirmed, you can return to your normal activities.
After the images have been interpreted, your radiologist or referring physician will discuss the findings with you. Depending on the results of the ultrasound, additional tests or procedures may be scheduled to gather further diagnostic information.